On using CCleaner, when I open Chrome, it says preferences are corrupt and all settings/apps/extensions get removed.

After displaying the corrupt preferences message, the wrench becomes orange coloured and on clicking it, I see “New Extension Added (Download Accelerator Plus)” even though I have uninstalled this extension.

or
1) Close Google Chrome
2)Go to Run, and press: Copy Paste the: %LOCALAPPDATA%Google
3) Right-click on the "Chrome" folder, and then click "Restore previous versions".
4) Click to select a version, and then click "Restore...".
5) A confirmation window will popup ("Are you sure you want to restore..."). Click Restore.
6) Windows should then copy some files to restore Chrome, finishing with the message:
"The folder has been successfully restored to the previous version."
7) Click OK to close the message, then close the Properties and Explorer windows.
8) Launch Google Chrome